Previously known tire chains have numerous disadvantages, including heavy weight, breakage and damage to tires when in use and inconvenience in transporting the same.
Conventional snow chains include tire chain structures comprising a plurality of metal rings around the tire. Other snow chains have been provided with cross cables and side cables, in which the cross cables have plastic, elastic and flat strip shapes which serve as anti-skid bodies. Other known tire chains include chains in which both ends of the cross cables are fixedly connected with the side cables by rivets, or other fasteners. Still other chains are known, made of flat strips of elastic materials. Tire chains made with flat strips of elastic materials such as plastics are light in weight, convenient to transport and also do not break or damage the tires on which they are mounted. In spite of these advantages, the flat strip shaped, elastic material chains are not widely used because:
The shape of the cross cables tend to stay flat, forcing the side cables apart, not conforming to the cross section of the tire, making it hard to tighten the chains around the tire so that they will remain in position during use.
The (elastic) material of which the cross cables are made does not slide easily over the tread of the tire, High frictional forces between the tire and the elastic material of the cross cable, make it hard to keep the cross cables evenly spaced and tighten the chain.
The fixed connection between the cross cables and the side cables become bent and deformed when assembeling the chains to the tire causing the chains to be even harder to tighten.
Japanese Utility Model Publication No. 1990-2643 (published on Jan. 23, 1990) discloses a cross member comprising a wire cable and a plurality of ball bodies mounted on the wire cable. This cross member has advantages for readily mounting on the tire and reducing noise, but the structure possesses no effective anti-skid function.
U.S. Pat. No. 4,660,611 ("Tire Chain", patented on Apr. 28, 1989) describes an improved tire chain employing heat treated medium carbon steel elements assembled including a pair of side members, fastening means to secure one end of each side member to the other end, and a plurality of cross chains extending between the side wall members at preselected intervals. The tire chain is considerably more durable, but the structure provides no effective anti-skid functions.